Optical media players and recorders, such as current compact disc (CD) and digital video disc (DVD) systems operate generally by directing an optical beam from a source, causing the beam to contact a specific location on an optical medium where data is stored, and receiving the data via the reflection of the beam back to receiving devices. To make this happen, current systems are required, at least, to perform two necessary functions, which are tracking and focusing.
Focusing involves fine-tuning the manner in which the optical beam impinges upon the optical medium. Tracking involves placing the beam (and consequently the source of the beam) in a specific location so it will impinge upon the optical medium in the appropriate place. Thus, in a current optical media player and/or recorder, the optical media typically is rotated and an optical beam is continually both focused onto the media and moved (using tracking functionality) to the appropriate place on the media, so that the data can be reflected back to a receiving device and output, for instance to a speaker and/or a television.
Therefore, a current optical media player operates generally as shown in FIG. 1 in order to allow a user to listen to a song or watch a movie. The player 100 holds an optical medium 110, such as a CD or DVD. The medium 110 is caused to spin, and a light source 120 directs an optical beam 130 to the medium 110. The beam 130 then reflects back to a receiving device 140 where a focusing function 150 and a tracking function 160 work in tandem to make beam 130 both the in the right shape and in the right place. As time passes (through a combination of spinning the medium 110 and the tracking function 160), the beam 130 may be directed across the entire spiral track 170 so that the entire CD or DVD can be watched, recorded, and/or listened to. Similarly, the beam 130 can be moved between tracks, for instance track A 180 and track B 191, when the user jumps between scenes and/or songs.
Current tracking systems involve moving the light source 120, typically an optical head apparatus 195 along the disc in the radial direction 196 using a sled 197. A motor 198 is usually used to apply the force needed to move the optical head apparatus 195 in the radial direction 196. This was considered necessary in order to finally focus the beam to a point on a disc via an objective lens in the optical head apparatus 195.
When nearly instant data access is of utmost importance, the time it takes for the motor 198 to move the optical head apparatus 195 to the appropriate location in the radial direction 196 is problematic, specifically when it needs to jump between tracks. Additionally, when the player and/or recorder is first turned on, the time it takes to cause the disc to initially begin rotating is also lengthy.
Thus, re-writable optical recorders have consistently had drawback s that have prevented them from being used as an alternative storage medium to replace the hard disc. Some have proposed using a voice coil to move the optical head instead of a motor, yet the optical head is still massive enough that even with a very powerful voice coil, the movement is slow and cumbersome, resulting in fairly long seek times. This results in a delay when moving between tracks or when the player is turned on and play begins, which can be problematic.